you can use this :
<?php
$update = "";
foreach($_POST as $key => $value) {
if(!empty($value)) {
$update .= $key. "='".$value."',";
}
}
$update = substr($update,0,-1);
$query = "UPDATE table_name SET ".$update." WHERE id=$id";
?>
solved PHP: Create SQL query for available $_POST variable [closed]